1. Home
  2. Electronics Repair
  3. Faint Horizontal lines on top 1/4 of television screen

Faint Horizontal lines on top 1/4 of television screen

Hello,

I have an old Montgomery Wards (Sharp) television, model JSJ2220. It has the problem of a number of faint horizontal lines in the top 1/4 of the screen. Some of the lower lines have brighter "dashes" in them, some of which blink. At the bottom of the lines is one line that is composed of colors like a rainbow.

I have searched the group, and read that problems of this type are often attributed to electrolytics in the Vertical section. Unfortunately, I do not have a schematic, and the circuit board isn't laid out with a diagram showing roughly what does what.

If you have any suggestions as to what the problem might be, or which components would likely be the culprits, I would be most appreciative.

Thank you,

Jon

Reply to
Jon Danniken
Loading thread data ...

CORRECTION: model number JSJ12220

Sorry for the mistake.

Jon

Reply to
Jon Danniken

Bad boost capacitor in the vertical circuit. The vertical output will fail soon if not fixed - it's presently running too hot.

Mark Z.

Reply to
Mark D. Zacharias

Thanks Mark. Any idea which capacitor it is? I don't have a schematic for the unit.

Jon

Reply to
Jon Danniken

look at the caps near anything hot or burnd spots, my tv did this 2

for

fail

Reply to
crazy frog

Lots are in the range of 100uF at 35 volts, near the vertical output. This is all just generic advice, BTW - don't know your model.

Mark Z.

Reply to
Mark D. Zacharias

...but your advice will be dead on correct. :-)

Tom

Reply to
Tom MacIntyre

"Jon Danniken" bravely wrote to "All" (07 Oct 05 19:14:05) --- on the heady topic of "Re: Faint Horizontal lines on top 1/4 of television = screen (model corre"

Replace *all* electros around a 1" vicinity of the vertical IC. Cost of the electros is minimal and one might not have to go back in there for longer a while than if we just replaced the faulty one. Consider that commonly it takes more time to take things apart than to actually make a repair.

A*s*i*m*o*v

JD> From: "Jon Danniken" JD> Xref: core-easynews sci.electronics.repair:344431

JD> Thanks Mark. Any idea which capacitor it is? I don't have a JD> schematic for the unit.

JD> Jon

... If all else fails, hurl it across the room a few times!

Reply to
Asimov

It's a good idea to change all the electrolytic caps in the vertical deflection.

I.

Reply to
buran

Thank you Mark, and others. I located my Vertical IC (don't laugh), a uPC1378 variant, as well as five different electrolytics in the section. One of these is actually a 100uF at 35 volts, just as you predicted.

Am I going to want to special order a "low ESR" cap for a replacement? My local parts store only carries "regular" caps; otherwise I'll have to go through digikey.

Thanks again, and I apologize for the delayed response to this.

Jon

Reply to
Jon Danniken

Get the 105 degrees C version at least. Low ESR likely isn't important.

Tom

Reply to
Tom MacIntyre

This

My

Thanks, Tom. I ended up ordering the batch through digikey, low ESR 105C jobs, since they were about as cheap as the other ones anyway. The only outlet in town had the same old dried up electrolytics they've had for the last 10 years, and the TV repair place wanted $7.20 for just *one* cap (I guess that's their way of saying they don't want to sell me caps, lol).

Jon

Reply to
Jon Danniken

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.